With a small form factor of 15 x 27 mm for the SPWF01S, it packs a lot of architecture. The module integrates flash memory that is in addition to the flash memory of the microcontroller. The STM32 microcontroller with 512 K of memory plus the possibility to have 1 MB of flash with the SPWF01S1 module. The Wi-Fi module integrates the crystals, the low frequency and the high frequency crystal. This is an added value for the customer, the end user does not have to connect, for example, the low frequency crystal to the module. The antenna is on board, but it can also be provided with the option of U.FL connector with a different part number. All of the voltage regulators are already inside the device, which means that 3.3 V will power up the device. For the interface, the module has a UART and also a certain number of GPIOs that can be used to communicate with the module as well, like turning on or off some LED during the communication. The radio has an integrated PA that allows it to have an output power of 18 dBm. This is an important factor because an external PA on the module is not needed, so that is a cost-savings of the module.